Particularly, in medical fields such as a clinical site, it is necessary to detect a cell infected with a pathogen or a cell having a predetermined mode from many cells. For example, WO 2010/027003 discloses a technique of rapidly, simply, and accurately detecting the cell. In the technique of WO 2010/027003, plural micro chambers (wells) are formed on a micro chip array, and each well is filled with fluorescently-labeled cells. Each well is observed with a fluorescent microscope while irradiated with a laser beam, and thereby a specific cell that yields fluorescence is detected.
Unexamined Japanese Patent Publication No. 2006-322819 discloses a configuration in which a series of wells filled with the cells is scanned with the laser beam to detect the fluorescence yielded from the cell. In the configuration of Unexamined Japanese Patent Publication No. 2006-322819, the series of wells is formed in a circumferential direction of a disk, and a series of information pits is formed on a layer on a light incident side separated from a layer in which the well is formed, the series of information pits being formed into a track shape so as to be arranged along an array of the wells. Address information is held in the information pit.
In the configuration of Unexamined Japanese Patent Publication No. 2006-322819, a light source that emits excitation light to the well and a light source that emits a laser beam to the information pit are separately prepared in an optical system that detects the fluorescence, and the light emitted from each light source is caused to converge by a common objective lens. The objective lens is controlled such that the laser beam for the information pit is focused on the information pit to follow an information pit string (track). Therefore, the excitation light is focused on the cells filling the well and the series of wells is sequentially scanned with the laser beam. The optical system includes a photodetector that detects the fluorescence yielded from the cell and a photodetector that receives the laser beam modulated by the information pit. A signal used to control the objective lens and a signal used to reproduce information held in the information pit are generated from output of the photodetector that receives the laser beam.
When the fluorescence is yielded from the cell irradiated with the excitation light, the fluorescence is detected by the photodetector that detects the fluorescence. A position of the well in which the cell yielding the fluorescence is accommodated is identified by positional information that is acquired from the information pit in detecting the fluorescence. The existence or non-existence of a detection target cell and the position of the well in which the cell is accommodated are automatically detected from many cells accommodated in the series of wells provided on the disk without the fluorescence microscope observation.